Articles including undenatured meat protein and water condensed from steam

ABSTRACT

An article includes a mixture release component defining a mixture release volume and also includes a heated mixture located within the mixture release volume. The heated mixture includes undenatured meat protein and water condensed from steam. A mixture release opening is included at an outlet end of the mixture release volume and this mixture release opening defines a passage from the mixture release volume to a vacuum chamber volume defined by a vacuum chamber. A vacuum is applied to the vacuum chamber volume. The steam from which the water has condensed comprises steam that has been placed in direct contact with a stream of undenatured meat protein in a direct steam injector having a mixture outlet operatively connected to the mixture release component.

CROSS-REFERENCE TO RELATED APPLICATION

Applicant claims the benefit, under 35 U.S.C. § 120, of U.S. patentapplication Ser. No. 16/792,949 filed Feb. 18, 2020, and entitled“Systems and Methods for Receiving the Output of a Direct StreamInjector.” The entire content of this prior application is incorporatedherein by this reference.

Applicant also claims the benefit, under 35 U.S.C. § 119(e), of U.S.Provisional Patent Application No. 62/808,778 filed Feb. 21, 2019, andentitled “Direct Heating Medium Injector and Injection System andMethod.” The entire content of this provisional application isincorporated herein by this reference.

TECHNICAL FIELD OF THE INVENTION

The invention relates to neutralizing pathogens in undenatured meatproteins by steam injection, and to articles containing treatedundenatured meat proteins.

BACKGROUND OF THE INVENTION

Heat treatment is used in the food processing industry to eliminatepathogens and for other purposes. For example, milk may be heated toabout 145° for about thirty minutes, or to about 162° F. for aboutfifteen seconds to destroy or deactivate disease-causing microorganismsfound in milk. These heat treatment processes are commonly referred toas pasteurization. Milk or cream may also be treated by heating to 280°F. to 302° F. for two to six seconds (or more) in a process referred toas ultra-high-temperature (“UHT”) pasteurization. Pasteurization and UHTpasteurization may not entirely sterilize the product being treated, butmay be effective for killing or deactivating biological pathogens oragents present in the product.

Heat treatment of liquid or otherwise pumpable materials like milk andcream may be indirect or direct. In indirect heat treatment systems, theheating medium remains separate from the foodstuff and heat istransferred to the foodstuff in a heat exchange device such as a shelland tube or plate-type heat exchanger. In contrast to indirect heattreatment systems, direct heat treatment systems bring the foodstuffinto direct contact with steam. Although this direct contact adds waterto the foodstuff being treated, that added water may be separated fromthe treated foodstuff as desired.

Direct steam heat treatment systems may be divided generally into steaminfusion systems and steam injection systems. In steam infusion systems,steam is directed through a steam inlet into a suitable steam chamberand the product to be treated is directed into the steam chamber througha separate product inlet, commonly a diffuser plate including a numberof passages through which relatively fine streams of product may flowinto the steam chamber. U.S. Pat. No. 4,591,463 describes examples ofsteam infusion systems. In steam injection systems, steam may beinjected into a stream of foodstuff flowing through a conduit to rapidlyincrease the temperature of the foodstuff to a desired treatmenttemperature. The added steam and product may then be held at an elevatedtemperature for a desired time by causing the mixture to flow through ahold conduit. U.S. Pat. No. 2,022,420 provides an example of a steaminjection system.

In both steam infusion and steam injection systems, the water added tothe product during treatment may be removed from the product by applyinga vacuum sufficient to vaporize the added water and then drawing off thewater vapor. This vaporization of added water also has the effect ofrapidly decreasing the temperature of the now heat-treated product. Inthe case of steam infusion systems, the water and heated product areremoved from the steam chamber and then directed to a vacuum chamber forapplying the desired vacuum. In the case of steam injection systems, themixture of heated product and added water is directed from the holdconduit into a vacuum chamber where the added water is vaporized and maybe drawn off along with any remaining steam.

Although direct steam injection systems are commonly used for heattreating foodstuffs such as milk and juices, problems remain whichincrease the cost of operating such systems. Perhaps the most persistentproblem encountered in direct steam injection systems is the depositionof materials from the product, milk proteins in the case of milktreatment for example, on surfaces within the steam injector anddownstream from the injector. These deposits can reduce flow through thesystem and must be removed periodically to allow proper operation. Thisremoval of deposits necessitates the shut-down of the treatment systemand these shut downs increase operation costs and reduce productivity.In applications beyond dairy products, deposition may be so rapid thatpassages carrying the product to be treated become completely plugged ina very short period of time, a few seconds or a few minutes. Thedeposition problem thus prevents prior direct steam injection systemsfrom being used for heat treating certain products, such as productsincluding raw (that is, uncooked) meat proteins or egg proteins.

SUMMARY OF THE INVENTION

An article according to an aspect of the present invention includes amixture release component defining a mixture release volume and alsoincludes a heated mixture located within the mixture release volume. Theheated mixture includes undenatured meat protein and water condensedfrom steam. A mixture release opening is included at an outlet end ofthe mixture release volume and this mixture release opening defines apassage from the mixture release volume to a vacuum chamber volumedefined by a vacuum chamber. A vacuum is applied to the vacuum chambervolume. The steam from which the water has condensed comprises steamthat has been placed in direct contact with a stream of undenatured meatprotein in a direct steam injector having a mixture outlet operativelyconnected to the mixture release component. The operative connectionhere is a connection that facilitates a flow of material from themixture outlet of the direct steam injector to the mixture releasevolume.

In some embodiments the mixture release opening is located within thevacuum chamber volume. Additionally, the operative connection betweenthe mixture outlet of the direct steam injector and the mixture releasecomponent may include a hold conduit operatively connected between themixture outlet of the direct steam injector and an inlet to the mixturerelease component so as to facilitate the flow of material from themixture outlet of the direct steam injector to the mixture releasevolume defined by the mixture release component. Where a hold conduit isincluded in the article, at least some of the hold conduit may belocated within the vacuum chamber volume.

In some implementations of an article within the scope of the presentinvention, surfaces defining at least some of the mixture release volumeare located within the vacuum chamber volume and these surfaces are insubstantial thermal communication with a mixture release componentcooling structure. As used here and elsewhere in this disclosure and thefollowing claims, “substantial thermal communication” with a surfacemeans in thermal contact with the surface across one or more heatconductive materials so as to facilitate the transfer of heat in adirection from the surface away from the flow path across the one ormore heat conductive materials to effect reasonable control of thetemperature of the surface. For example, a cooling structure such as acoolant fluid circulating chamber separated from a given surface by awall of material 0.25 inches thick or less having a thermal conductivityof at least approximately 10 W/m K would be in substantial thermalcommunication with the given surface. A thicker wall at this thermalconductivity could still provide substantial thermal communicationwithin the scope of the present invention, albeit with reducedcapability of providing the desired temperature control. Additionalexamples of structures in substantial thermal communication with a givensurface will be described below in connection with the illustratedembodiments. It has been found that cooling some of the surfacesdefining the mixture release volume prevents undue deposition of productconstituents, even in cases where the product being treated comprises aproduct that could not previously be treated by direct steam injection,such as products including undenatured (raw) meat proteins for example.

In some implementations including a hold conduit connected between themixture outlet of the direct steam injector and the release component,at least some of the surfaces defining the mixture flow path through thehold conduit are in substantial thermal communication with a mixtureflow path cooling structure. Both the mixture release component coolingstructure and the mixture flow path cooling structure associated withthe hold conduit may comprise respective coolant fluid circulatingchambers. These coolant fluid circulating chambers (specifically amixture release component coolant fluid circulating chamber and amixture flow path coolant fluid circulating chamber) may be seriallyconnected for communicating coolant fluid.

In some embodiments the mixture release component includes a nozzle andthe mixture release opening comprises a nozzle outlet to the vacuumchamber volume. In these embodiments the nozzle may be located withinthe vacuum chamber volume. Additionally, surfaces of the nozzle may bein substantial thermal communication with a nozzle surface coolingstructure such as a nozzle coolant fluid circulating chamber and atleast some of the nozzle surface cooling structure may be located withinthe vacuum chamber volume.

In embodiments where the mixture release component includes a nozzle,the nozzle may include a nozzle surface defining a cone shape. This coneshape is oriented so that the shape increases in diameter along a nozzleaxis toward the nozzle outlet to the vacuum chamber volume. Embodimentsincluding a cone-shaped nozzle may include any of the variationsdescribed above in connection with nozzles in general. Namely, thenozzle surface defining the cone shape may be located within the vacuumchamber volume and at least some of the cone-shaped surface may be insubstantial thermal communication with a nozzle surface coolingstructure such as a nozzle coolant fluid circulating chamber.

The undenatured meat protein in the mixture release volume may be at atemperature to effectuate destruction or deactivation of pathogens thatmay be in the heated mixture. This temperature may be within a rangebetween approximately 158° F. and approximately 200° F.

The vacuum applied to the vacuum chamber volume may be a vacuumsufficient to ensure that substantially all moisture in the heatedmixture added as a consequence of the direct steam injection isconverted to vapor within the vacuum chamber volume to both facilitaterapid cooling of the undenatured meat protein released into the vacuumchamber volume and to facilitate removal of the moisture from theundenatured meat protein. A suitable pressure applied to the vacuumchamber volume through a suitable port to the vacuum chamber may bebetween approximately 29.5 inches of mercury to approximately 25.5inches of mercury.

These and other aspects, advantages, and features of the invention willbe apparent from the following description of representativeembodiments, considered along with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a steam injection systemembodying principles of the present invention.

FIG. 2 is a schematic representation showing the location at which aheated mixture may be released in the vacuum chamber shown in FIG. 1 .

FIG. 3 is a longitudinal section view of a portion of a hold conduitwithin the scope of the present invention.

FIG. 4 is a transverse section view taken along line 4-4 in FIG. 1 .

FIG. 5 is a schematic representation of a steam injection system similarto that shown in FIG. 1 , but having an alternate hold conduitarrangement in accordance with the present invention.

FIG. 6 is a schematic representation of an alternate steam injectionsystem embodying principles of the present invention.

FIG. 7 is a schematic representation showing the location at which aheated mixture may be released in the vacuum chamber shown in FIG. 6 .

DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

Referring to FIG. 1 , a steam injection system 100 includes a steaminjector (direct steam injector) 101 and a vacuum chamber 102. Vacuumchamber 102 includes a vacuum port 105 connected by a suitable vacuumconduit 106 to a vacuum source 108, and also includes an outlet port 109connected by a suitable product outlet conduit 110 to an output pump111. Steam injection system 100 also includes a mixture flow path whichextends from injector 101 to vacuum chamber 102. In this case themixture flow path is defined by a hold conduit 104 extending from steaminjector 101 to a location within the interior of vacuum chamber 102,that is, a location within vacuum chamber volume 103.

Vacuum chamber 102 comprises a suitable vessel which defines the vacuumchamber volume 103. In particular, vacuum chamber 102 includes lateralwalls 114, a top wall 115 and cone-shaped bottom wall 116 which togetherdefine vacuum chamber volume 103. Vacuum chamber 102 may be elongatedalong a vertical axis V as shown in FIG. 1 , and may be generallycylindrical in shape along that axis. This vertical orientation ofvacuum chamber 102 provides operational advantages which will bedescribed further below in connection with the operation of steaminjection system 100. However, implementations of a steam injectionsystem according to the present invention are by no means limited to usewith a vacuum chamber with a vertical orientation as shown in theexample of FIG. 1 .

Steam injector 101 is located outside of vacuum chamber volume 103 andincludes a steam inlet 120 and a product inlet 121. Steam injector 101also includes a mixing structure shown generally at 122 in FIG. 1 , anda mixture outlet 124. Generally, mixing structure 122 includes astructure in which a steam path 125 and product path 126 merge withinthe injector to allow the steam and relatively cooler product to mix tothereby effect a rapid temperature increase in the product to a desiredtreatment temperature. Mixing structure 122 may, for example, include asuitable chamber formed within injector 101 which includes a suitableinlet from steam path 125 and a suitable inlet from product path 126 toprovide the desired mixing of the steam and product. Mixture outlet 124comprises an outlet from steam injector 101 through which the heatedmixture, that is, heated product, any remaining steam, and any condensedwater, may exit the steam injector.

Examples of direct steam injectors that may be used in a steam injectionsystem according to the present disclosure such as steam injectionsystem 100 are described in U.S. Pat. No. 10,674,751 entitled “HeatingMedium Injectors and Injection Methods for Heating Foodstuffs.” Itshould be appreciated, however, that although steam injectors accordingto the above-noted patent are well suited for use in steam injectionsystems according to the present invention, other direct steam injectorsmay be employed for steam injector 101 shown in FIG. 1 .

The mixture flow path defined in this example system 100 by hold conduit104 begins at a mixture inlet opening 104A operatively connected tomixture outlet 124 of steam injector 101. The mixture flow path definedby hold conduit 104 includes a segment generally indicated at referencenumeral 127 which is located outside of vacuum chamber volume 103 and asegment generally indicated at reference numeral 128 which is locatedwithin the vacuum chamber volume. In this particular implementation,hold conduit 104 extends to an outlet end 104B connected to a nozzle 132which is located substantially in the center of vacuum chamber volume103 along the vacuum chamber vertical axis V. Nozzle 132 in this examplerepresents a release component situated to release a heated mixture intovacuum chamber volume 103. The extension of hold conduit 104 into thevacuum chamber volume 103 is shown also in FIG. 2 . The mixture flowpath shown in FIG. 1 terminates at the nozzle surfaces 133 of nozzle132. These nozzle surfaces 133, which define a mixture release volume inthis example, make up the surfaces of the flow path segment 128 adjacentto a mixture release opening 133A (defined at the lowermost end ofnozzle surfaces 133 in the orientation of FIG. 1 and representing anozzle outlet in this example) to the vacuum chamber volume. Inparticular, mixture release opening 133A in this example is located atan outlet end of the mixture release volume defined by nozzle surfaces133 and defines a passage from the mixture release volume to the portionof the vacuum chamber volume 103 external to the mixture releasecomponent. As will be described further below in connection with theoperation of steam injection system 100, nozzle 132 is adapted to causethe material (heated mixture) exiting the mixture flow path and mixturerelease volume defined by the nozzle to form a downwardly-opening,cone-shaped stream indicated by dashed lines 136 in FIG. 1 .

In example system 100, the surfaces of the mixture flow path along itsentire length are in substantial thermal communication with a coolingstructure. The cooling structure in this example comprises a coolantfluid circulating chamber shown generally at reference numeral 137extending along the entire length of the mixture flow path includingboth segment 127 and segment 128 (and including along the nozzlesurfaces 133 defining the mixture release volume in this example). Thusin this example, coolant fluid circulating chamber 137 includes both amixture flow path structure (chamber portion along hold conduit 104) anda nozzle surface cooling structure (chamber portion along nozzlesurfaces 133). A coolant inlet port 138 to coolant fluid circulatingchamber 137 is fed by coolant supply line 139 and a coolant outlet port140 is connected to a coolant return line 141. Coolant supply line 139and coolant return line 141 are each operatively connected to a coolantsupply 144. It will be appreciated by those skilled in the art thatcoolant supply 144 may include a suitable cooling or refrigeratingsystem and a circulating pump, neither of which are shown in thedrawing. The cooling or refrigerating system functions to cool asuitable coolant fluid to a desired temperature as will be describedfurther below, while the circulating pump functions to direct thecoolant fluid to coolant fluid circulating chamber 137 through coolantsupply line 139 and coolant inlet port 138. Coolant return line 141allows the coolant fluid to return to coolant supply 144 once thecoolant fluid has flowed along the length of coolant fluid circulatingchamber 137. It should be noted here that coolant fluid circulatingchamber 137 is preferably isolated from the mixture flow path so thatthere is no mass transfer from the coolant fluid circulating chamber 137to the mixture flow path or vice versa, that is, no mixing of coolantfluid and product being treated. The coolant fluid circulating chambersdescribed below for other implementations according to the inventionlikewise isolate the respective chambers from the respective mixtureflow path.

The section views of FIGS. 3 and 4 show an implementation of the holdconduit 104 and cooling structure represented by coolant fluidcirculating chamber 137 shown schematically in FIG. 1 . In particular,FIG. 3 comprises a section view of a portion of the length of the holdconduit 104 and cooling structure according to a particular embodiment.It can be assumed that this short length of the structure represents aportion encompassing the section line 4-4 in FIG. 1 . The transversesection view of FIG. 4 can be assumed to be along section line 4-4 inFIG. 1 . As such, FIGS. 3 and 4 show both the hold conduit 104, coolantfluid circulating chamber 137, and a flow passage representing a portionof coolant return line 141. The particular implementation of FIGS. 3 and4 includes an elongated cylindrical body 146 having a cylindricalpassage which provides a portion of coolant return line 141. A largercylindrical passage defined by surface 147 receives hold conduit 104 soas to define an annular flow path around the hold conduit and thisannular flow path represents coolant fluid circulating chamber 137. Theinternal surface 148 of hold conduit 104 defines the mixture flow paththrough the conduit while the outer surface 149 of hold conduit 104defines an inner surface of coolant fluid circulating chamber 137. Inthis arrangement, a coolant fluid introduced into coolant fluidcirculating chamber 137 may flow along the annular chamber definedbetween surfaces 147 and 149 in the direction from the left to the rightin the orientation of FIG. 1 , and indicated by arrows F in FIG. 3 .Coolant fluid that has travelled the length of hold conduit 104 flowsalong the passage defining coolant return line 141 in the directionindicated by arrow R. The flow of coolant fluid as indicated by arrows Fplaces the coolant fluid in position to facilitate a transfer of heatfrom the surface 148 of the hold conduit as the product and steammixture flow along hold conduit 104 in the direction indicated by arrowP in FIG. 3 . This heat transfer is across the wall of hold conduit 104defined between inner surface 148 and outer surface 149, which ispreferably as thin as possible to facilitate better heat transfer. Forexample, this wall defined between inner surface 148 and outer surface149 may be preferably formed from a suitable food handling gradematerial such as a stainless steel having a relatively high thermalconductivity, preferably over approximately 10 W/(mK).

In the operation of system 100, and referring particularly to FIG. 1 ,steam is introduced into steam inlet 120 of injector 101 and directedalong steam flow path 125 to mixing structure 122 while the product tobe treated, such as undenatured meat protein for example, is introducedinto product inlet 121 and directed along product path 126 to mixingstructure 122. The two streams mix within mixing structure 122 to form aheated mixture of heated product, any remaining steam, and any watercondensed from the steam, and this heated mixture stream exits injector101 through mixture outlet 124. From injector 101, the mixture includingheated product and water condensed from the applied steam is directedthrough hold conduit 104, both segment 127 and segment 128, to nozzle132 within the vacuum chamber volume 103 which defines the mixturerelease opening 133A for the heated mixture stream within the vacuumchamber volume. Hold conduit 104 has a sufficient volume and the flowrate is controlled so that the product being treated is held at thedesired elevated treatment temperature for a desired period of timebefore being released into vacuum chamber volume 103 through mixturerelease opening 133A of nozzle 132. Thus, in the example where theproduct is undenatured meat protein, just prior to release of the heatedmixture though mixture release opening 133A into vacuum chamber volume103, the undenatured meat protein in the heated mixture within themixture release volume defined by nozzle surfaces 133 is at the desiredtreatment temperature (in a range between approximately 158° F. andapproximately 200° F. as described further below) and present togetherwith water condensed from the steam applied in injector 101.

Once the heated mixture stream of heated product, any remaining steam,and water that has been condensed from the steam is released into thevacuum chamber volume, the relatively low pressure (which may be betweenapproximately 29.5 inches of mercury to approximately 25.5 inches ofmercury for example) causes the water in the mixture to vaporize so thatit can be drawn off through vacuum port 105 together with any remainingsteam. The vaporization of the water within vacuum chamber volume 103rapidly reduces the temperature of the now treated product and thecooled product may collect in the bottom of vacuum chamber 102 where itmay be drawn off through outlet port 109 and outlet conduit 110 byoutput pump 111. In this particular system, output pump 111 pumps thetreated product through system outlet conduit 112 for furtherprocessing. The downwardly facing cone-shaped stream produced by nozzle132 in system 100 has the effect of increasing the surface area ofliquids in the released stream to enhance the vaporization of water forremoval through vacuum port 105. The position of nozzle 132 in thecenter of vacuum chamber 102 together with the downwardly facing nozzlearrangement helps ensure that product does not contact the internalsurfaces of the vacuum chamber walls 114 and 116 immediately uponrelease from the nozzle into the vacuum chamber volume 103. This helpsprevent significant deposition of product constituents on the innersurfaces of the vacuum chamber walls.

While the mixture of heated product, remaining steam, and any condensedwater flows through hold conduit 104 from left to right in theorientation of FIG. 1 , coolant supply 144 is operated to direct coolantfluid through coolant inlet line 139 to inlet port 138. The coolantfluid may then flow along the length of coolant fluid circulatingchamber 137 (including the portions adjacent to nozzle surfaces 133) tocoolant outlet port 140 within the vacuum chamber volume, and thenreturn to coolant supply 144 through coolant return line 141. Thecoolant fluid is supplied at a temperature and at a flow rate sufficientto cool the surfaces making up the inner surface of conduit 104, such asinner surface 148 in the implementation shown in FIGS. 3 and 4 , and tocool the nozzle surfaces 133. As described in more detail in thefollowing paragraph, this cooling inhibits the deposition ofconstituents from the product along the surfaces of hold conduit bothalong segment 127 outside the vacuum chamber volume and along segment128 within the vacuum chamber volume, and including the nozzle surfaces133.

Where cooling structures are used to cool surfaces so as to reducedeposition rates according to aspects of the present invention, thetemperature to which the given surface is cooled is a temperature belowtemperatures at which product tends to adhere to a surface. Thistemperature will vary with the product being treated. For productsincluding undenatured meat or egg proteins, for example, surfaces whichare cooled by a cooling structure may be cooled to a temperature no morethan approximately 135° F., and more preferably no more thanapproximately 130° F. Some products may tend to adhere to surfaces athigher temperatures than this example, while still other products maytend to adhere to surfaces at lower temperatures. The cooling structuresin each case are operated in accordance with the invention to reach thedesired operating temperature to resist the deposition of productconstituents in operation of the injector according to the presentinvention.

Temperatures at which a given product tends to adhere to a surface mayalso vary with the total hold time for which the product is treated. Fora given product, the surface temperature at which the product begins toadhere may be higher for shorter hold times and lower for longer holdtimes. Generally, it is not necessary to actively monitor the mixtureflow path surfaces in order to maintain the surfaces at the desiredoperating temperature. Rather, cooling is performed as needed to limitthe deposition of product constituents to an acceptable level.

Operating parameters of a steam injection system incorporating aspectsof the present invention will depend in some cases on the particularproduct which is being treated and thus included in the heated mixturereceived from the direct steam injector such as injector 101 in FIG. 1 .In particular, the treatment temperature and hold time along the mixtureflow path will depend in large part upon the product being treated andthe goal of the heat treatment. Where the product includes raw meat oregg proteins which are to remain undenatured over the course of thetreatment, the goal of the treatment may be to destroy pathogens such asEscherichia coli (E. coli) O157:H7, Salmonella, Listeria, andCampylobacter bacteria and in this case the target treatment temperaturefor the product in the heated mixture stream may be betweenapproximately 158° F. and approximately 200° F. and the hold time atthat temperature until release into the vacuum chamber may be less thanone second. Of course, the present invention is by no means limited tothis temperature range and hold time, which are provided merely as anexample of operation.

It will be noted from the example described above for products includingraw meat or egg proteins that the treatment temperature of approximately158° F. to approximately 200° F. is well above the temperature of asurface at which the product tends to adhere to the surface, namely,approximately 135° F. for example. Thus without the surface cooling inaccordance with the present invention, surfaces within a hold conduitsuch as 104 in FIGS. 1-4 would quickly reach the adherence temperatureand product deposits would quickly form. Cooling surfaces in accordancewith the present invention prevents the given surfaces from reaching theadherence temperatures and thus reduces or eliminates product depositionon those surfaces.

In view of the function of coolant fluid circulating chamber 137 toprovide a way to cool (remove heat from) the hold conduit inner surface148 and nozzle surfaces 133, it will be appreciated that it is desirablein the operation of steam injection system 100 to ensure the coolantfluid flows throughout the chamber volume. In order to ensure thisdesired flow throughout the volume of the coolant fluid circulatingchamber 137, and to ensure appropriate mixing of the coolant fluid,various dams, baffles, and other flow directing features, as well asturbulence inducing elements may be included within coolant fluidcirculating chamber 137. Suitable flow directing features for used incoolant fluid circulating chambers or cooling jackets are well known inthe art of heat exchange devices and are thus not shown either in theembodiment of FIGS. 3 and 4 or the schematic drawings of FIGS. 1 and 2 .

The inner surface 148 of hold conduit 104 in FIGS. 3 and 4 is insubstantial thermal communication with the cooling structure comprisingcoolant fluid circulating chamber 137 by virtue of the thermalconductivity from which the hold conduit is formed (preferably overapproximately 10 W/m K combined with the thickness of the material,which may be only approximately 0.02 inches to approximately 0.05 inchesfor example). Substantial thermal communication may also be providedthrough a thicker wall of material. Other arrangements providingsubstantial thermal communication between coolant fluid circulatingchamber 137 and a hold conduit inner surface such as surface 148 in theexample of FIGS. 3 and 4 , may include multiple layers of materialresiding between the coolant fluid circulating chamber and inner wall.For example, a conduit such as conduit 104 may be formed from a thinlayer of material having a first thermal conductivity and a second layerhaving the same or higher thermal conductivity.

The vertically oriented vacuum chamber 102 shown for example in FIG. 1represents one preferred configuration because the orientation allowsthe heated mixture to be released at a location within the vacuumchamber volume that is well spaced-apart from vacuum port 105. Thisprevents product in the released heated mixture from being drawn out ofthe vacuum chamber through vacuum port 105. The vertically orientedvacuum chamber 102 and center release location well above the bottomwalls 116 shown in FIG. 1 also enhances exposure of the released heatedmixture to the reduced pressure maintained in the vacuum chamber.However, other vacuum chamber orientations may be used within the scopeof the present invention. Also, although FIG. 1 shows vacuum chamber 102having a cone-shaped bottom wall 116, a rounded bottom wall or otherbottom wall arrangement may be used within the scope of the presentinvention.

FIG. 5 shows an alternate steam injection system 500 according to thepresent invention. System 500 includes a steam injector 501, vacuumchamber 502, vacuum source 508, output pump 511, coolant supply 544, andhold conduit 504 similar to that shown for system 100. Unlike system100, system 500 includes a cooling structure for hold conduit 504 whichis divided into two components. In particular, system 500 includes aseparate cooling structure for portions of hold conduit 504 outside ofthe vacuum chamber volume 503 defined by vacuum chamber walls 514, 515,and 516, and a separate cooling structure for portions of the holdconduit within the vacuum chamber volume. This bifurcated coolingstructure in system 500 includes a suitable coolant fluid circulatingchamber 537A with a coolant inlet port 538A fed by coolant input line539A, and a coolant outlet port 540A connected to a coolant return line541A. The portion of the cooling structure associated with the segmentof hold conduit 504 within the vacuum chamber volume 503 includes acoolant fluid circulating chamber 537B having a coolant inlet port 538Bfed by coolant input line 539B, and a coolant outlet port 540B connectedto coolant supply 544 through coolant return line 541B. The twodifferent cooling structures shown in system 500 may be desirable toensure that the desired level of cooling is provided for surfaces alongall of hold conduit 504. The operation of system 500 is similar to thatdescribed above for system 100 except that coolant fluid is circulatedthrough both coolant fluid circulating chamber 537A and coolant fluidcirculating chamber 537B simultaneously while the mixture of heatedproduct, remaining steam, and condensed water is directed through holdconduit 504 to the release opening at nozzle 532 within the vacuumchamber volume 503.

FIG. 6 shows an alternate steam injection system 600 which includes adifferent arrangement for introducing the mixture of heated product,remaining steam, and any condensed water into the vacuum chamber volume603. Similarly to steam injection system 100 shown in FIG. 1 , system600 includes a steam injector 601 and a vacuum chamber 602 having walls614, 615, and 616 defining vacuum chamber volume 603. Vacuum chamber 602is connected to a vacuum source 608 and an output pump 611 similarly tosystem 100 shown in FIG. 1 and described above. System 600 in FIG. 6also includes a hold conduit 604 which extends from steam injector 601to vacuum chamber 602. A cooling structure is provided for hold conduit604 comprising a coolant fluid circulating chamber 637A connected to acoolant supply 644A by coolant inlet port 638A and coolant inlet line639A and by coolant outlet port 640A and coolant return line 641A. Inthe embodiment of FIG. 6 , however, the mixture flow path is not formedentirely by a hold conduit or hold conduit and nozzle. Rather, holdconduit 604 defines a segment of the mixture flow path from steaminjector 601 to vacuum chamber wall 614, and the segment of the mixtureflow path within vacuum chamber volume 603 is defined by an innersurface of wall 614 of the vacuum chamber itself. As shown in FIG. 7 ,hold conduit 604 intersects vacuum chamber wall 614 essentiallytangentially so that as the mixture flows out of the hold conduit itflows along the inner surface of vacuum chamber wall 614 as indicated byarrow HP in FIG. 7 . Thus the liquids included in the mixture spread outin a thin layer along the inner surface of wall 614 (which represents adispersal wall) in position to allow the vacuum applied to chambervolume 603 to vaporize water included in the mixture.

Because part of the mixture flow path is defined by the inner surface ofvacuum chamber wall 614, system 600 further includes an arrangementaccording to the invention for inhibiting the deposition of constituentsfrom the heated product on surface 617. Specifically, in the example ofFIGS. 6 and 7 system 600 includes a cooling structure in substantialthermal communication with the inner surface of vacuum chamber wall 614.The illustrated cooling structure comprises a coolant fluid circulatingchamber 637B having a coolant inlet port 638B fed by coolant inlet line639B from coolant supply 644B. A coolant outlet port 640B and coolantreturn line 641B allow the coolant to return to coolant supply 644B. Asecond cooling structure associated with vacuum chamber 602 in examplesystem 600 includes a coolant fluid circulating chamber 637C, connectedto receive coolant from coolant supply 644B through coolant inlet port638C and coolant inlet line 639C, and connected to return coolant to thecoolant supply through coolant outlet port 640C and coolant outlet line641C.

In operation of system 600 shown in FIGS. 6 and 7 , as the mixture ofheated product, remaining steam, and condensed water flows from steaminjector 601 through hold conduit 604, the coolant supply 644Acirculates a coolant fluid through coolant fluid circulating chamber637A to cool the inner surface of the hold conduit similarly to thecooling for conduit 104 as described above in connection with system100. Coolant supply 644B also circulates a coolant fluid through coolantfluid circulating chamber 637B in position to cool (remove heat from)the inner surface of vacuum chamber wall 614, and through coolant fluidcirculating chamber 637C in position to cool the inner surface of vacuumchamber wall 616. The cooling of the inner surface of hold conduit 604inhibits the deposition of material on those surfaces, while the coolingof the inner surface of vacuum chamber wall 614 and inner surface ofwall 616 inhibits the deposition of materials on those surfaces.

The invention encompasses numerous variations on the above-describedexample systems. Such variations include variations related to thecooling structures described in the above examples. Generally, where acooling structure is employed to remove heat from a surface forming partof a mixture flow path, the cooling structure may include any number ofsegments or elements to accomplish the desired cooling. For example, anynumber of separate or connected coolant fluid circulating chambers maybe included for a given surface. Also, although the illustrated examplesassume a certain direction of circulation through the coolantcirculation chambers, the direction of circulation may be reversed fromthat described. Furthermore, the invention is not limited to coolingstructures comprising coolant fluid circulating chambers to provide thedesired cooling. Thermoelectric devices may also be used to provide thedesired cooling of a given surface according to the present invention,as may forced air cooling arrangements in which air is forced over finsor other heat conductive arrangements in substantial thermalcommunication with the surface to be cooled. A cooling structure withinthe scope of the invention may also employ evaporative cooling to removeheat from the desired flow path surfaces. Also, different types ofcooling structures may be used for different areas of a given surface tobe cooled.

Another variation on the illustrated examples that lies within the scopeof the present invention includes an arrangement in which the entiremixture flow path between the mixture outlet of the direct steaminjector and the release point is located within the vacuum chambervolume. For example, the direct steam injector in the system may belocated above the top wall of the vacuum chamber with a hold conduitextending downwardly into the vacuum chamber volume. It is furtherpossible that both the injector and the entire mixture flow path resideswithin the vacuum chamber volume. In this case both the injector and thehold conduit may be suspended or otherwise mounted in the vacuum chambervolume. In either of these cases the surfaces of the mixture flow pathare, in accordance with the present invention, in thermal communicationwith one or more cooling structures.

For a given portion of a mixture flow path, a cooling structure may beimmediately adjacent to the surface to be cooled. However, coolingstructures such as coolant fluid circulating chambers may not becontinuous, but may include dividers, baffles, turbulence inducingfeatures, and other structures which prevent the coolant fluidcirculating chamber from being continuous along a given surface. Sucharrangements in which the coolant fluid circulating chamber may not becontinuous over a given surface to be cooled remain within the scope ofthe present invention as set out in the claims.

It is also possible within the scope of the present invention thatcooling structures do not extend along an entire mixture flow path orportion of the mixture flow path. For example, while FIGS. 1 and 5indicate that the cooling structure (coolant circulating chamber 137 inFIG. 1 and chambers 537A and 537B in FIG. 5 ) extend along the entirehold conduit and the respective nozzle, portions along the length of thegiven hold conduit and nozzle (or other mixture release structure) mayinclude no cooling structure. In some cases, depending upon the materialbeing treated, treatment temperature, and hold time, it may besufficient that the given surface is formed in a material which isresistant to deposit formation without active cooling. In particular,surfaces downstream from the steam injector in a treatment system may beformed in a temperature moderating material. As used in this disclosure,a “temperature moderating material” (sometimes referred to herein as“TMOD material”) comprises a material having a specific heat of no lessthan approximately 750 J/kg K, and preferably no less than approximately900 J/kg K, and, more preferably, no less than approximately 1000 J/kgK. A class of materials particularly suited for use as a TMOD materialin accordance with the present invention comprises plastics which have aspecific heat of no less than approximately 1000 J/kg K and are suitablefor providing food contact surfaces, retain structural integrity,maintain dimensional stability, and do not degrade at temperatures whichmay be encountered in a steam injection system. Regardless of thespecific TMOD material, “formed in” the given material means that thesurface is either molded, machined, extruded, or similarly formed in orfrom a mass of the material, or formed by an additive manufacturingtechnique such as 3D printing, either with or without polishing or othertreatment to achieve a desired surface smoothness.

Of course, where the product being treated is a foodstuff orpharmaceutical, a TMOD material must also be suitable for providing foodcontact surfaces. Suitable plastics for use as TMOD material includepolyetherether ketone (PEEK), Nylon, Ultra-high-molecular-weightpolyethylene (UHMWPE), polytetrafluoroethylene (Teflon),polyoxymethylene (POM or Acetal), and poly methyl methacrylate(acrylic), for example. These plastics suitable for use as TMOD materialin accordance with the present invention may include various additivesand may be used in both an unfilled composition or a filled (composite)composition, such as glass-filled or carbon-filled, provided the filledmaterial remains suitable for food contact, retains the desired specificheat as described above in this paragraph and is capable of providingthe desired surface finish. Materials other than plastics may also beemployed for TMOD material within the scope of the present invention.These materials include ceramics such as porcelain, glasses such asborosilicate glass (Pyrex) and rubber. These materials also includealuminum which has a specific heat of approximately 900 J/kg K and athermal conductivity of approximately 240 W/m K, as well as magnesiumand beryllium and alloys of these materials and Albemet. Materialshaving a specific heat of somewhat less than approximately 750 J/kg Kbut exhibit relatively high thermal conductivity may also represent asuitable substitute for a TMOD material. Such materials may have aspecific heat of no less than approximately 650 J/kg K and a thermalconductivity of no less than approximately 100 W/m K and include siliconcarbide for example. Also, a TMOD material within the scope of thepresent invention may comprise a mixture of materials and need notcomprise a single material. For example, a TMOD material may comprise amixture of different types of thermoplastics, or plastics and othermaterials such as quartz and epoxy resin composite materials forexample, or may be made up of layers of metals, plastics, and othermaterials and combinations of such materials in different layers. A TMODmaterial also need not be continuous along a given surface. For example,a given surface formed in a TMOD material according to the presentinvention may be formed in PEEK over a portion of its length and may beformed in a different plastic or other TMOD material over anotherportion of its length.

It is also possible in accordance with the present invention to utilizecooling structures together with TMOD materials. Although not limited tosuch materials, this use of cooling structures is particularlyapplicable to TMOD materials such as Aluminum having high thermalconductivity. A given surface may be both formed in a TMOD material andbe in substantial thermal communication with a cooling structureaccording to the following claims.

In the example treatment system configuration shown in FIG. 1 , some orall of the inner surface of hold tube 104 and some or all of nozzleinner surface 133 may be formed from a TMOD material for someapplications. The TMOD material would be in lieu of coolant circulatingchamber 137 or other cooling structure in these areas. In the exampleconfiguration of FIG. 5 , some or all of the inner surface of hold tube504 and some or all of the inner surfaces of nozzle 532 may be formedfrom a TMOD material for some applications of the system. The TMODmaterial would be in lieu of coolant circulating chambers 537A and 537Bor other cooling structure in these areas. In the example configurationshown in FIG. 6 , some or all of the inner surface of hold tube 604 andsome or all of the inner surface of wall 614 may be formed from a TMODmaterial in lieu of a cooling structure in these areas. Furthermore,some implementations of the present invention may employ coolingstructures only over a portion of the length of the heated mixture pathsuch as hold conduit 104 in FIG. 1 , while other portions of the lengthof the heated mixture path do not include a cooling structure and arenot formed in a TMOD material. Referring to FIG. 1 for example, coolantcirculating chamber 137 may not extend along the entire length of holdconduit 104. One or more portions along the length of hold conduit 104either inside or outside the volume of vacuum chamber, may not be insubstantial thermal communication with any adjacent cooling structureand may not be formed from TMOD material.

Surfaces which come in contact with the mixture of heated product,steam, and condensed water should have at least a suitable finishappropriate for the given product being treated in accordance with foodhandling standards. Generally, the surface roughness of any surfaceforming a portion of the mixture flow path should have a value of 32 RAmicroinches or less. Lower surface roughness values may enhance thedeposition inhibiting performance of a cooled surface in accordance withthe invention.

It will be appreciated that numerous connections, connectors, andfittings are required for connecting the various components included ina steam injection system embodying the principles of the presentinvention. These connections may be made with any suitable connectingstructure or arrangement. For connections between elements defining themixture flow path, the transition should be smooth and avoid changes inflow area.

The manner in which the heated mixture stream is released into a vacuumchamber such as vacuum chamber 102 in FIG. 1 is also subject tovariation within the scope of the present invention. Although FIG. 1shows a cone-shaped nozzle 132, other types of devices may be used torelease the heated mixture from the hold conduit 104, preferably in thinstreams of material. For example, rather than the illustrated nozzle132, hold conduit 104 may terminate in a release chamber having a numberof downwardly facing orifices sized to produce relatively thin streamsof material in the vacuum chamber volume below the release level. Inthese cases, all of the surfaces of the release chamber to which theheated mixture stream or part of it is exposed are in substantialthermal communication with a cooling structure associated with therelease chamber. As another example, the heated mixture may be releasedin the vacuum chamber volume via an impingement nozzle. As with othernozzle arrangements in accordance with the present invention, surfacesof an impingement nozzle which come in contact with the heated mixturemay be in substantial thermal communication with a cooling structure.This includes the structure of the impingement nozzle on which theheated mixture stream impinges.

In the arrangement shown in FIGS. 6 and 7 in which the vacuum chamberwall 614 forms a portion of the mixture flow path, the entire surface ofwall 614 need not be in thermal communication with a cooling structure.For example, coolant fluid circulating chamber 637B may not extend allthe way down wall 614 to bottom wall 616. Rather, coolant fluidcirculating chamber 637B may extend essentially from the level of vacuumchamber 603 at which heated mixture is released into the vacuum chamberto a lower level which is spaced apart from bottom surface 616 such thatthere is a vertical gap between the lowermost part of coolantcirculating chamber 637B and wall 616 (and any coolant circulatingchamber such as chamber 637C which is included along wall 616).Additionally, since the heated mixture may not contact the inner surfaceof wall 614 around the entire circumference of vacuum chamber 603, acoolant circulating chamber such as chamber 637B may extend along only apart of the circumference of the vacuum chamber, generally along onlythat portion of the wall 614 which is contacted by the heated mixturewhile components of the mixture are at a temperature at which depositsmay form on the wall for a given material being treated. It may also beunnecessary for a given implementation to include any cooling structurefor the bottom wall 616, and thus coolant circulating chamber 637C maybe omitted in some systems in accordance with the principles of thepresent invention.

It should also be appreciated that while the system shown in FIG. 1 doesnot include any cooling structures for cooling the inner surfaces wall116 at the bottom of vacuum chamber 102, cooling structures may beincluded along these walls as well. Such a cooling structure maycomprise a structure such as that shown in the embodiment of FIG. 6 forwall 1016 for example. The inner surfaces of wall 116 in FIG. 1 do notrepresent surfaces which define the mixture flow path because themixture has been subjected to the reduced pressure in vacuum chamber 102for a substantial period of time before reaching wall 116. However, atleast for some products to be treated, it may still be desirable forcooling the inner surfaces of wall 116 to reduce product deposition onthese surfaces.

The mixture flow path in the cooled hold conduit 104 shown in FIGS. 3and 4 is shown as plain cylindrical flow paths. It will be appreciatedthat a certain amount of mixing may be desired in the mixture of heatedproduct, steam, and water as the mixture flows along the flow path toensure the product being treated is evenly heated. This mixing may beaccomplished in some implementations of the invention by includingfeatures along the mixture flow path to induce turbulence. Mixinginducing features along the mixture flow path may include various shapedprotrusions that extend in to the flow path from a conduit wall orrecesses in the conduit wall, or may include changes in shape of theinner surface defining the mixture flow path such that such innersurfaces define non-linear surfaces in the direction of flow. It will beappreciated that such mixing or turbulence-inducing features alsoinclude surfaces comprising surfaces of the mixture flow path. Thus thesurfaces of any mixing or turbulence-inducing features within the holdconduit may also be in substantial thermal communication with one ormore cooling structures.

As used herein, whether in the above description or the followingclaims, the terms “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” and the like are to be understood to beopen-ended, that is, to mean including but not limited to. Also, itshould be understood that the terms “about,” “substantially,” and liketerms used herein when referring to a dimension or characteristic of acomponent indicate that the described dimension/characteristic is not astrict boundary or parameter and does not exclude variations therefromthat are functionally similar. At a minimum, such references thatinclude a numerical parameter would include variations that, usingmathematical and industrial principles accepted in the art (e.g.,rounding, measurement or other systematic errors, manufacturingtolerances, etc.), would not vary the least significant digit.

Any use of ordinal terms such as “first,” “second,” “third,” etc., inthe following claims to modify a claim element does not by itselfconnote any priority, precedence, or order of one claim element overanother, or the temporal order in which acts of a method are performed.Rather, unless specifically stated otherwise, such ordinal terms areused merely as labels to distinguish one claim element having a certainname from another element having a same name (but for use of the ordinalterm).

The term “each” may be used in the following claims for convenience indescribing characteristics or features of multiple elements, and anysuch use of the term “each” is in the inclusive sense unlessspecifically stated otherwise. For example, if a claim defines two ormore elements as “each” having a characteristic or feature, the use ofthe term “each” is not intended to exclude from the claim scope asituation having a third one of the elements which does not have thedefined characteristic or feature.

The above described preferred embodiments are intended to illustrate theprinciples of the invention, but not to limit the scope of theinvention. Various other embodiments and modifications to thesepreferred embodiments may be made by those skilled in the art withoutdeparting from the scope of the present invention. For example, in someinstances, one or more features disclosed in connection with oneembodiment can be used alone or in combination with one or more featuresof one or more other embodiments. More generally, the various featuresdescribed herein may be used in any working combination.

1. An article including: (a) a mixture release component defining amixture release volume; (b) a mixture release opening at an outlet endof the mixture release volume, the mixture release opening defining apassage from the mixture release volume to a vacuum chamber volumedefined by a vacuum chamber, a vacuum being applied to the vacuumchamber volume; and (c) a heated mixture located within the mixturerelease volume, the heated mixture including undenatured meat proteinand water condensed from steam that has been placed in direct contactwith a stream of undenatured meat protein in a direct steam injectorhaving a mixture outlet operatively connected to the mixture releasecomponent to facilitate a flow of material from the mixture outlet ofthe direct steam injector to the mixture release volume.
 2. The articleof claim 1 wherein: (a) the mixture release component includes a nozzle;and (b) the mixture release opening comprises a nozzle outlet to thevacuum chamber volume.
 3. The article of claim 2 wherein the nozzle islocated within the vacuum chamber volume and the nozzle outlet to thevacuum chamber is to a portion of the vacuum chamber external to thenozzle.
 4. The article of claim 3 wherein the nozzle includes a nozzlesurface at least some of which is in substantial thermal communicationwith a nozzle surface cooling structure.
 5. The article of claim 4wherein the nozzle surface cooling structure includes a nozzle coolantfluid circulating chamber connected to receive a nozzle coolant fluidcirculated therethrough.
 6. The article of claim 4 wherein at least someof the nozzle surface cooling structure is located within the vacuumchamber volume.
 7. The article of claim 6: (a) further including a holdconduit operatively connected between the mixture outlet of the directsteam injector and an inlet to the nozzle to facilitate a flow ofmaterial from the outlet of the direct steam injector to the mixturerelease volume defined by the nozzle; and (b) wherein at least some ofthe hold conduit is located within the vacuum chamber volume.
 8. Thearticle of claim 7 wherein at least some of the hold conduit locatedwithin the vacuum chamber volume is in substantial thermal communicationwith a mixture flow path cooling structure.
 9. The article of claim 2wherein the nozzle includes a nozzle surface defining a cone shapehaving an increasing diameter in a direction along a nozzle axis towardthe nozzle outlet to the vacuum chamber volume.
 10. The article of claim9 wherein the nozzle surface defining the cone shape is located withinthe vacuum chamber volume and the nozzle outlet to the vacuum chamber isto a portion of the vacuum chamber external to the nozzle.
 11. Thearticle of claim 10 wherein at least some of the nozzle surface definingthe cone shape is in substantial thermal communication with a nozzlesurface cooling structure.
 12. The article of claim 11 wherein thenozzle surface cooling structure includes a nozzle coolant fluidcirculating chamber connected to receive a nozzle coolant fluidcirculated therethrough.
 13. The article of claim 1 wherein the mixturerelease opening is located within the vacuum chamber volume and thepassage from the mixture release volume to the vacuum chamber volume isto a portion of the vacuum chamber external to the mixture releasecomponent.
 14. The article of claim 13: (a) further including a holdconduit operatively connected between the mixture outlet of the directsteam injector and an inlet to the mixture release component so as tofacilitate the flow of material from the mixture outlet of the directsteam injector to the mixture release volume defined by the mixturerelease component; and (b) wherein at least some of the hold conduit islocated within the vacuum chamber volume.
 15. The article of claim 14wherein surfaces defining at least some of the mixture release volumeare located within the vacuum chamber volume and are in substantialthermal communication with a mixture release component coolingstructure.
 16. The article of claim 15 wherein surfaces defining atleast some of a mixture flow path through the hold conduit are insubstantial thermal communication with a mixture flow path coolingstructure.
 17. The article of claim 16 wherein the mixture releasecomponent cooling structure includes a mixture release component coolantfluid circulating chamber and the mixture flow path cooling structureincludes a mixture flow path coolant fluid circulating chamber connectedserially with the mixture release component coolant fluid circulatingchamber.
 18. The article of claim 1 wherein the undenatured meat proteinin the mixture release volume is at a temperature within a range betweenapproximately 158° F. and approximately 200° F.
 19. The article of claim1 wherein the vacuum applied to the vacuum chamber volume is betweenapproximately 29.5 inches of mercury to approximately 25.5 inches ofmercury.
 20. The article of claim 1 wherein: (a) the undenatured meatprotein in the mixture release volume is at a temperature within a rangebetween approximately 158° F. and approximately 200° F.; and (b) thevacuum applied to the vacuum chamber volume is between approximately29.5 inches of mercury to approximately 25.5 inches of mercury.